Stop mechanism for knitting machines



June 21, 1938.

J. WACHSMAN ET AL STOP MECHANISM FOR KNITTING MACHINES Filed June 18, 1937 Fig.3

JR (0B WACHSMA N MIC/ H5! W/KHSM/M/ IN VEN TORS BUM 5.

A TTORNEY Patented June 21, 1938 I UNITED STATES PATENT OFFlQE STOP MECHANISM FOR KNITTING MACHINES Application June 18, 1937, Serial No. 148,854

2 Claims.

This invention relates to stop mechanisms for knitting machines of the type disclosed in Reissue Patent 19,069, February 6, 1934 to Jacob Waohsman and has also reference to Patent 2,080,903, May 18, 1937 to Michael Wachsman.

Stop motions or mechanisms and parts thereof of the type disclosed in these two patents are well known in the art and need not be described in detail.

The said reissue patent discloses the combination of two thread supporting levers with an overhanging fixed guard. One of the levers is a spring held or tension knot detector lever. The other lever is a gravity actuated end detector lever. The overhanging fixed guard serves the purpose of preventing a rise of the end detector lever to an electric circuit closing portion because of a mere slack in the thread. Where such a slack occurs the thread will be lifted by the end detector lever up against the guard into a position in which the thread straddles the lever and thus prevents the latter from rising by gravity into a still higher position in which said lever makes a contact to close an electric circuit which in turn causes the knitting machine to stop.

In practise the guard also functions as a selfthreading member for the stop motion in that the thread is placed upon or threaded upon the levers by merely placing the thread upon the guard. The latter has a forwardly and downwardly inclined member. The thread therefore slides down the guard into position upon the levers without any further attention by the operator.

The said other Patent No. 2,080,903 discloses a tension lever for electric stop motions in which the selfthreading feature is incorporated in the lever itself. For this purpose the lever has an upstanding guard member. The thread is thrown upon or placed against this member and then slides down into position upon the lever.

The object of the present invention is to provide a stop motion which embodies a selfthreading guard member according to the said reissue patent together with certain features which are disclosed in the said other patent. The result is a new simple stop mechanism embodying certain improved features not found in either of the said two patents.

In the accompanying drawing Fig. 1 is a side View partly in section and with parts omitted of a stop mechanism embodying the invention.

Fig. 2 is a plan view thereof.

Fig. 3 is a detail View of a contact spring.

In the drawing the reference numeral 6 denotes a housing or box made in any suitable manner and provided with a lug 1 whereby it may be attached to a knitting machine. 8 denotes a contact spring which is secured to a fixed electric terminal 9 suitably insulated from the box. The terminal 9 is as usual included in the electric stop circuit not shown. In the sides ID of the box are notches H for pivoting the spring held lever l2 which inside the box is provided with a contacting heel l3 adapted to contact the spring 8 so as to close the electric circuit. The lever I2 is held in a normal operative position by a spring 14 having adjusting means IS. The contact spring 8 may conveniently be divided as at I6 to permit passage of the spring M as will be explained hereinafter.

The lever H! has two forwardly extending arms [1, II which are covered with porcelain fingers I 8, l8. The latter are shaped to provide thread supporting portions l9 and overhanging noses 20 which form a thread enclosing space 2i with an entrance for the thread at 22.

At 24 there is secured to the lug 7 a guard member which preferably consists of a piece of wire bent to form forwardly and downwardly extending threading portions 25 which are then bent back to form horizontal thread retaining portions 26. The latter are then bent upwardly to form lateral stop portions 27. The ends of the guard may be attached by a screw or rivet at 24.

Fig. 1 shows the part in normal operating position with the thread 30 placed upon the fingers l8 underneath the portions 2| of the guard. The spring M will be adjusted to just balance the Weight and the pull of the thread upon the lever. When a knot or other obstruction occurs in the thread, the latter can no longer run over the porcelain fingers. The thread then pulls down the lever l2 into a position in which the thread slips off the porcelain fingers and the contact heel I3 is raised against the force of the spring Hi. This position is indicated by the dotted line 32. The spring now pulls the lever down into a position indicated approximately by the other dotted line 34 and the contact heel now engages the spring 8 and closes the electric circuit in a well known manner which need not be described herein. The knitting machine then stops. The thread supporting lever is now held by the spring [4 against the lateral stop portions 21 on the guard and as seen in Fig. 1 the thread may now be put back into the stop motion by dropping it upon the lever in front of the inclined guard portion 25 and then pulling the lever down into normal position. As the lever moves down the thread will slide down the guard and in under the nose 36 thereof into the enclosed space 2| of the finger l8.

When a slack occurs the lever will be moved upward by the spring l4 but not high enough to cause contact to be made because the guard portions 2| overlie the thread and prevent rise of the lever into contact making position.

If the thread breaks or runs out the weight thereof will be removed from the lever which will immediately be pulled down into contact making position by the spring 14.

It will be noted that when a knot occurs on the thread the lever will first be moved down into position 32 before the spring can move it into contact making position at 34. Thus there will be a hardly perceptible delay before contact is made. Such a slight delay is practically of no importance. It may be avoided however by providing the contact spring with an upstanding finger 38 so that when the lever is moved down by the thread contact will be immediately made with said finger 38. It will be understood that inasmuch as the upper end of the spring follows the movement of the contact heel it will necessarily pass across the contact portion of the spring 8, that is it will pass through the space l6 provided in the spring.

The construction herein disclosed includes several advantages over prior structures. In the first place, the entire mechanism is of extreme simplicity which makes for accessibility, cleanliness and efiicient operation. The thread enclosing space 2| in combination with the overhanging guard is of decided advantage. It is a well known fact that the thread in knitting machines does not run in a steady straight line but vibrates and bobs up and down due. to the high speed of the machines, the variation in diameters of the bobbins and that in the summer time when windows are open in the plant, the threads are blown about and are thus apt to be blown into or against the stop mechanisms. In this instance the thread has space within the enclosed space 2| which on the one hand permits free movement of the thread and eliminates friction and strain. On the other hand the porcelain fingers are so shaped that the thread is confined and cannot be blown out of position.

Another advantage is that when the lever has been raised by the spring into the position indicated at 34, it forms a Wide. angle with the guard which facilitates replacing and rethreading.

We claim:

1. In a knitting machine a stop mechanism under control of a travelling thread, a circuit closer unit comprising a housing, a fixed electrical terminal secured thereto, a single spring held lever pivoted in said housing including thread receiving and supporting fingers, said lever serving both as a knot detector and an end detector for a thread placed upon said fingers, a spring for balancing said lever in a normal operative position against the weight of a thread placed upon said fingers, a contact heel on said lever, said spring continuously tending to move said contact heel into. engagement with the said fixed terminal and a fixed guard on said housing to hold the lever against engaging said terminal so long as a thread lies upon the fingers of the lever.

2. In a knitting machine a stop mechanism under control of a travelling thread, a circuit closer unit comprising a housing, a single thread supporting lever pivoted in said housing, porcelain members on said lever forming thread receiving fingers and overhanging noses spaced from said fingers to form thread enclosing spaces, means for balancing said pivoted lever in normal operative position against the weight of the thread placed upon said thread supporting fingers, a fixed guard on said housing having horizontally disposed thread restraining portions in cooperative relation with the said thread enclosing fingers and noses, stop portions on said guard which the said lever is adapted to abut when it is swung above its pivot, an electric terminal spring contact within the housing and a contact heel upon said lever for contacting the said spring contact when the said lever is moved above or below its pivot by the removal of the thread from the said thread supporting fingers.

JACOB WACHSMAN. MICHAEL WACHSMAN. 

